This was classified for a long time as a study for the RN Aquila. Recent studies have shown a striking similarity to a Roma battleship class hull. With any probability it is a study to convert the still to be completed (at the time) battleship to a fleet carrier.
NOTE: this is not the final AC design studied in the forthcoming book.
The model is preserved at Museo storico navale di Venezia. Full info about the RN Impero here.